EP1446894B1 - Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel - Google Patents

Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel Download PDF

Info

Publication number
EP1446894B1
EP1446894B1 EP02803530A EP02803530A EP1446894B1 EP 1446894 B1 EP1446894 B1 EP 1446894B1 EP 02803530 A EP02803530 A EP 02803530A EP 02803530 A EP02803530 A EP 02803530A EP 1446894 B1 EP1446894 B1 EP 1446894B1
Authority
EP
European Patent Office
Prior art keywords
echo
threshold
input signal
power
far
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
EP02803530A
Other languages
German (de)
English (en)
Other versions
EP1446894A1 (fr
EP1446894A4 (fr
Inventor
Syuji Kubota
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Publication of EP1446894A1 publication Critical patent/EP1446894A1/fr
Publication of EP1446894A4 publication Critical patent/EP1446894A4/fr
Application granted granted Critical
Publication of EP1446894B1 publication Critical patent/EP1446894B1/fr
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
    • H04M9/082—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic using echo cancellers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers

Definitions

  • the present invention relates to echo canceller technology for howling prevention and echo control, which technology is required in hands-free telephones.
  • the function means of an echo canceller is formed mainly of a transversal filter and a coefficient modifier part that successively updates the coefficient of the filter.
  • NLMS normalized least mean squares
  • the normalized least mean squares (NLMS) algorithm which is excellent in stability and convergence, relatively simple in terms of operations, and actually realized as a device using an LSI, may be employed as a method of estimating, or updating, the filter coefficient ⁇ hi ⁇ of the transversal filter.
  • the echo canceller requires, as its important functions, an echo canceller protection function and a nonlinear processing (center clipper) function.
  • the echo canceller protection function prevents errors from being caused by the speech of a near-end talker in updating the tap coefficient (filter coefficient) at the time of two-way simultaneous communication (double talk).
  • the nonlinear processing function unconditionally suppresses a low echo signal to a zero value in order to increase the echo suppression effect when the echo level is low.
  • the nonlinear processing aims to reduce residual echo by adding a so-called voice switch that turns ON or OFF depending on a signal level.
  • Japanese Laid-Open Patent Application No. 4-150127 discloses such a technique.
  • Japanese Laid-Open Patent Application No. 10-285083 discloses a device that includes means for varying a clip level and changing transmitting attenuation depending on the condition of transmission.
  • Japanese Laid-Open Patent Application No. 9-162787 discloses a configuration that employs a low-pass filter setting a low cut-off frequency when signal power is low and setting a high cut-off frequency when signal power is high.
  • the residual echo of an echo-canceled signal includes a high-frequency component.
  • Offensive noise can be reduced by suppressing the high-frequency component.
  • the low-pass filter is employed as means for suppressing the high-frequency noise component.
  • noise suppression means includes power calculation means for calculating the power level of an input signal supplied from an echo cancellation part, comparison means for comparing the power level of the signal calculated by the power calculation means with a predetermined threshold for noise determination, and noise suppression means for performing noise suppression on the signal by the low-pass filter when the comparison result shows that the power level of the signal is lower than or equal to the predetermined threshold.
  • the low-pass filter of the noise suppression means varies the cut-off frequency so that the cut-off frequency is low when the signal power is low as residual echo and the cut-off frequency is high when the signal power is high as the speech signal of a near-end talker.
  • the low-pass filter of the noise suppression means is realized by moving average processing, and the variation in the cut-off frequency of the low-pass filter is realized by a variation in the moving average interval length of the moving average processing.
  • the low-pass filter (LPF) with a variable cut-off frequency of a simple configuration can be realized.
  • the power calculation means obtains the power of the signal expressed in the form of the exponent of 2 n by digital processing.
  • the comparison means obtains the number of moving average interval length bits m by subtracting the power level in the form of the exponent of 2 n from the noise determination threshold in the form of the exponent of 2 n .
  • the noise suppression means performs, by digital processing, moving average processing with respect to an interval length determined by the obtained number of moving average interval length bits m when m is not negative.
  • the noise suppression means compares the output power of the echo cancellation part with the predetermined determination threshold.
  • the determination threshold can be determined with no problem when the amount of residual echo or a near-end input power value can be estimated in advance. In the case of a great environmental variation, however, it is difficult to distinguish between the residual echo and the speech of the near-end talker, thus making it difficult to determine the determination threshold.
  • any signal that is smaller than the set threshold goes through the noise (residual echo) suppression means that is the LPF with a variable cut-off frequency.
  • the threshold setting lacks deliberation, low-power fricative consonants may be cut by bandwidth restriction.
  • the determination threshold is fixed to a low value, the function of suppressing residual echo does not work. This is because the residual echo temporarily increases at the early learning stage of the echo canceller or at the time of echo path change.
  • the echo path characteristic becomes nonlinear, thus increasing the residual echo.
  • the residual echo power exceeds the threshold in such a case, thus resulting in the problem that the residual echo is transmitted to the far-end side without going through the noise suppression part.
  • the determination threshold may be set to a high value so that such residual echo goes through the noise suppression part.
  • This problem is caused in a system where an echo coming out from a speaker to be input to a microphone has approximately the same magnitude as that of the speech of the near-end talker. For instance, this problem is caused in a handy phone system that requires a loudspeaker and a microphone to be arranged relatively close to each other or in an on-vehicle hands-free telephone system that outputs sound at high volume from a loudspeaker and requires a microphone to be arranged at a distance from the mouth of a speaker.
  • Japanese Laid-Open Patent Application No. 9-275367 discloses another technology.
  • Japanese Laid-Open Patent Application No. 9-275367 discloses an echo canceller device has the functions of (a) detecting the direction of communication depending on the condition of communication from an input signal from the far end (the speech of a far-end talker) and an input signal from the near end (the combination of the speech of a near-end talker and the echo sound of the speech of the far-end talker) and (b) gradually changing the cut-off frequency of an LPF for residual echo suppression every time the direction of communication changes.
  • WO 99/13596 and WO 97/23055 disclose echo signal methods and apparatus which have dynamic thresholds based on nonlinear power estimates.
  • a more specific object of the present invention is to provide an echo canceller that includes a noise determination function that is adaptive to the speech of a far-end talker so as to ensure further reduction in residual echo even if the residual echo increases at the early learning stage of the echo canceller or at the time of echo path change.
  • an echo canceller comprising: an echo cancellation part canceling echo included in a near-end input signal to the echo canceller, the near-end input signal including an echo component of a far-end input signal to the echo canceller; a noise suppression part employing a low-pass filter having a variable cut-off frequency adaptive to power of an input signal, the noise suppression part removing a residual echo component from an output of said echo canceller part; a threshold generation part configured to generate a threshold; a determination part making a determination based on a comparison between a power level of the output of said echo cancellation part and the variable threshold; and a processing part performing noise suppression using the low-pass filter on the output of said echo cancellation part when said determination part determines that the power level of the output of said echo cancellation part is lower than or equal to the threshold; characterised in that said threshold generation part generates the threshold using an exponent of a power level of the far-end input signal calculated in a form 2 k so that the threshold is variable in accordance with the power level
  • an echo canceller including: an echo cancellation part canceling echo included in a near-end input signal to the echo canceller, the near-end input signal including an echo component of a far-end input signal to the echo canceller; a noise suppression part employing a low-pass filter having a variable cut-off frequency adaptive to power of an input signal, the noise suppression part removing a residual echo component from an output of the echo canceller part; a first calculation part calculating a power level of the output of the echo canceller part; a second calculation part calculating a power level of the far-end input signal; a determination part making a determination based on a comparison between the power level of the output of the echo cancellation part and a variable threshold varying in accordance with the power level of the far-end input signal; and a processing part performing noise suppression using the low-pass filter on the output of the echo cancellation part when the determination part determines that the power level of the output of the echo cancellation part is lower than or equal to the variable threshold.
  • the threshold for noise determination can be set to a low value.
  • any signal smaller than a set threshold for noise determination is supplied to a noise (residual echo) suppression part that is a low-pass filter (LPF) with a variable cut-off frequency, so that the cut-off frequency of the LPF becomes lower as the power of a near-end input is decreased. Therefore, if the threshold setting lacks deliberation, low-power fricative consonants may be cut by bandwidth restriction.
  • the threshold for noise determination can be varied in accordance with the power of the far-end speech, so that the above-described disadvantage can be eliminated.
  • FIG. 1 is a diagram showing the configuration of an echo canceller according to the embodiment of the present invention.
  • the echo canceller of FIG. 1 includes an echo cancellation part 1 and a noise suppression part 2. According to this configuration, a signal x i output from the echo cancellation part 1 is input to the noise suppression part 2.
  • the echo cancellation part 1 has the same function as the conventional echo canceller. That is, the echo cancellation part 1 has the function of canceling echo by first generating a pseudo echo by supplying a reception signal to a filter simulating an echo path and then applying a phase-inverted pseudo echo to an input signal.
  • the echo cancellation part 1 further includes the double-talk function and the howling detection function in order to realize the hands-free communication function.
  • the noise suppression part 2 is formed of a low-pass filter that sets a low cut-off frequency when the power of an input signal is low and sets a high cut-off frequency when the power of the input signal is high. According to the echo canceller of FIG. 1 , the output of the echo cancellation part 1 is supplied to the noise suppression part 2 and thereafter, is transmitted as a transmission signal.
  • FIG. 2 is a diagram showing a common configuration of the noise suppression part 2.
  • a power calculation part 11 and a power exponent extraction part 12 calculate the power level of the output signal x i of the echo cancellation part 1. After the power level of the signal x i is thus calculated, it is determined, by comparing the power level of the signal x i with a threshold ths for noise determination, whether the signal x i is a high-power signal such as the speech of a near-end talker or a low-power signal such as residual echo or background noise.
  • the noise suppression part 2 includes the power calculation part 11, the power exponent extraction part 12, a subtraction part 13, a sign determination part 14, and a noise suppression processing part 15.
  • the power calculation part 11 calculates the power of the output signal x i of the echo cancellation part 1, that is, the power calculation part 11 converts the output signal x i into power.
  • the power exponent extraction part 12 expresses the power calculated by the power calculation part 11 in the form of 2 k , and extracts the value s of its exponent.
  • the subtraction part 13 obtains the number of moving average interval length bits m by subtracting the exponent value s of the power in the form of 2 k from the noise determination threshold ths , and determines the moving average interval length to be 2 m .
  • the sign determination part determines whether the number of moving average interval length bits m is negative or not.
  • the noise suppression processing part 15 performs noise suppression on the signal x i .
  • the noise suppression part 2 further includes an output selection part 16.
  • the output selection part 16 determines that the level of the output signal x i of the echo cancellation part 1 (that is, the signal input to the noise suppression part 2) is higher than the noise threshold ths and that the signal x i is the speech signal of the near-end talker to be transmitted. Therefore, the output selection part 16 outputs the as-input signal x i as the transmission signal without the signal x i being subjected to the noise suppression.
  • the output selection part 16 outputs the signal x i that has been subjected to the noise suppression in the noise suppression processing part 15 as the transmission signal.
  • the function of a low-pass filter (LPF) in the noise suppression processing part 15 is realized by moving average processing, and variations in the cut-off frequency of the LPF are realized by variations in the moving average interval length of the moving average processing.
  • LPF low-pass filter
  • FIG. 3 is a diagram showing the configuration of the noise suppression part 2 according to the embodiment of the present invention.
  • the noise determination threshold ths is prestored in the form of 2 k in a memory, for instance. If the noise determination threshold ths is fixed, however, the above-described problem occurs in an actual usage environment. Therefore, according to the present invention, a variable noise determination threshold is set using the input power of a far-end talker.
  • the noise suppression part 2 further includes a power calculation part 21, a power exponent extraction part 22, a subtraction part 23, a threshold limiter 24, and a addition part 25 for a far-end input signal in addition to the configuration of FIG. 2 .
  • the power of the far-end input signal is expressed in the form of 2 k , and the power exponent extraction part 22 extracts its exponent value r and sets r as the power level of the far-end input signal.
  • the subtraction part 23 subtracts a predetermined threshold thr for far-end speech power detection from the power exponent value r and obtains a subtraction result mr .
  • the subtraction result mr is multiplied by a parameter ⁇ for reflecting the far-end power to be output as a value thra.
  • the value thra goes through the limiter 24 so as to have its setting range limited so that the value thra may not be set to be higher or lower than required by the effect of the far-end power. Thereby, the output value thral of the limiter 24 is obtained.
  • the noise suppression part 2 of FIG. 3 performs the same operation as in the configuration of FIG. 2 .
  • the noise suppression part 2 of the present invention compares the power of the far-end signal and the output power of the echo cancellation part 1, using the calculated variable noise determination threshold thsr .
  • the noise determination threshold thsr is increased so that the residual echo may be cut by the LPF.
  • the determination threshold thsr is decreased so as to prevent the LPF from working on the near-end signal.
  • the noise determination threshold is varied using the input power of the far-end talker. Therefore, the residual echo component can be cut with more accuracy, so that its effect on a signal to be transmitted, such as the speech of the near-end talker, can be minimized. Thereby, a transmission signal that is so excellent as to be easy to hear can be obtained.
  • this function can be realized with a simple configuration, so that the amount of calculation can be reduced in realizing this function in a DSP.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Telephone Function (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Filters That Use Time-Delay Elements (AREA)

Claims (9)

  1. Annuleur d'écho comprenant:
    une partie d'annulation d'écho (1) annulant un écho inclus dans un signal d'entrée d'extrémité proche dans l'annuleur d'écho, le signal d'entrée d'extrémité proche incluant une composante d'écho d'un signal d'entrée d'extrémité éloignée dans l'annuleur d'écho ;
    une partie de suppression de bruit (2) employant un filtre passe-bas ayant une fréquence de coupure variable s'adaptant à la puissance d'un signal d'entrée, la partie de suppression de bruit enlevant une composante d'écho résiduelle d'une sortie de ladite partie d'annulation d'écho ;
    une partie de génération de seuil configurée pour générer un seuil ;
    une partie de détermination (14) effectuant une détermination sur la base d'une comparaison entre un niveau de puissance de la sortie de ladite partie d'annulation d'écho et le seuil variable ; et
    une partie de traitement (15) effectuant une suppression de bruit en utilisant le filtre passe-bas sur la sortie de ladite partie d'annulation d'écho lorsque ladite partie de détermination détermine que le niveau de puissance de la sortie de ladite partie d'annulation d'écho est inférieur ou égal au seuil ;
    caractérisé en ce que ladite partie de génération de seuil génère le seuil en utilisant un exposant d'un niveau de puissance du signal d'entrée d'extrémité éloignée calculé sous une forme 2k de sorte que le seuil soit variable conformément au niveau de puissance du signal d'entrée d'extrémité éloignée.
  2. Annuleur d'écho selon la revendication 1, dans lequel ladite partie d'annulation d'écho (1) annule l'écho inclus dans le signal d'entrée d'extrémité proche en générant un pseudo-écho et en appliquant un pseudo-écho à phase inversée au signal d'entrée d'extrémité proche, la partie d'annulation d'écho générant le pseudo-écho en fournissant le signal d'entrée d'extrémité éloignée à un filtre simulant un trajet d'écho.
  3. Annuleur d'écho selon la revendication 1, dans lequel la fréquence de coupure du filtre passe-bas de ladite partie de suppression de bruit (2) est diminuée lorsque la puissance du signal d'entrée est faible et est augmentée lorsque la puissance du signal d'entrée est élevée.
  4. Annuleur d'écho selon la revendication 1, comprenant en outre un limiteur de seuil (24) établissant une limite supérieure et une limite inférieure à un effet de puissance du signal d'entrée d'extrémité éloignée afin d'établir une limite supérieure et une limite inférieure au seuil variable.
  5. Annuleur d'écho selon la revendication 1, comprenant en outre :
    une première partie de calcul (11) calculant le niveau de puissance de la sortie de ladite partie d'annulation d'écho ; et
    une seconde partie de calcul (21) calculant le niveau de puissance du signal d'entrée d'extrémité éloignée.
  6. Annuleur d'écho selon la revendication 5, comprenant en outre un limiteur de seuil (24) établissant une limite supérieure et une limite inférieure à un effet de puissance du signal d'entrée d'extrémité éloignée afin d'établir une limite supérieure et une limite inférieure au seuil variable.
  7. Annuleur d'écho selon la revendication 6, dans lequel ladite partie de génération de seuil génère le seuil variable sur la base d'une sortie dudit limiteur de seuil.
  8. Annuleur d'écho selon la revendication 6, dans lequel ladite partie de génération de seuil génère le seuil variable sur la base d'une différence entre le niveau de puissance du signal d'entrée d'extrémité éloignée et un seuil prédéterminé.
  9. Annuleur d'écho selon la revendication 6, dans lequel ladite partie de suppression de bruit (2) comprend ladite partie de génération de seuil, ladite partie de détermination (14), ladite partie de traitement (15), ladite première partie de calcul (11), ladite seconde partie de calcul (21) et le limiteur (24).
EP02803530A 2001-11-20 2002-11-19 Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel Expired - Fee Related EP1446894B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2001355299 2001-11-20
JP2001355299A JP4282260B2 (ja) 2001-11-20 2001-11-20 エコーキャンセラ
PCT/JP2002/012068 WO2003044978A1 (fr) 2001-11-20 2002-11-19 Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel

Publications (3)

Publication Number Publication Date
EP1446894A1 EP1446894A1 (fr) 2004-08-18
EP1446894A4 EP1446894A4 (fr) 2006-02-01
EP1446894B1 true EP1446894B1 (fr) 2010-05-12

Family

ID=19167024

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02803530A Expired - Fee Related EP1446894B1 (fr) 2001-11-20 2002-11-19 Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel

Country Status (5)

Country Link
US (1) US7203308B2 (fr)
EP (1) EP1446894B1 (fr)
JP (1) JP4282260B2 (fr)
DE (1) DE60236367D1 (fr)
WO (1) WO2003044978A1 (fr)

Families Citing this family (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7856097B2 (en) * 2004-06-17 2010-12-21 Panasonic Corporation Echo canceling apparatus, telephone set using the same, and echo canceling method
US7890323B2 (en) 2004-07-28 2011-02-15 The University Of Tokushima Digital filtering method, digital filtering equipment, digital filtering program, and recording medium and recorded device which are readable on computer
US8457614B2 (en) 2005-04-07 2013-06-04 Clearone Communications, Inc. Wireless multi-unit conference phone
US8275120B2 (en) * 2006-05-30 2012-09-25 Microsoft Corp. Adaptive acoustic echo cancellation
TW200830706A (en) * 2007-01-12 2008-07-16 Sanyo Electric Co Filter coefficient setting device and echo prevention device
US8050398B1 (en) 2007-10-31 2011-11-01 Clearone Communications, Inc. Adaptive conferencing pod sidetone compensator connecting to a telephonic device having intermittent sidetone
US8199927B1 (en) 2007-10-31 2012-06-12 ClearOnce Communications, Inc. Conferencing system implementing echo cancellation and push-to-talk microphone detection using two-stage frequency filter
CN101453244A (zh) * 2007-11-28 2009-06-10 博通集成电路（上海）有限公司 线回波消除器
WO2010106820A1 (fr) 2009-03-19 2010-09-23 有限会社ケプストラム Dispositif d'annulation de sifflement
JP5493817B2 (ja) * 2009-12-17 2014-05-14 沖電気工業株式会社 エコーキャンセラ
US8515089B2 (en) 2010-06-04 2013-08-20 Apple Inc. Active noise cancellation decisions in a portable audio device
US9099077B2 (en) 2010-06-04 2015-08-04 Apple Inc. Active noise cancellation decisions using a degraded reference
US8824437B2 (en) * 2011-03-02 2014-09-02 Ricoh Company, Ltd. Wireless communications device, electronic apparatus, and methods for determining and updating access point
US9554207B2 (en) 2015-04-30 2017-01-24 Shure Acquisition Holdings, Inc. Offset cartridge microphones
US9565493B2 (en) 2015-04-30 2017-02-07 Shure Acquisition Holdings, Inc. Array microphone system and method of assembling the same
CN105516859B (zh) * 2015-11-27 2019-04-16 深圳Tcl数字技术有限公司 消除回声的方法和系统
US10367948B2 (en) 2017-01-13 2019-07-30 Shure Acquisition Holdings, Inc. Post-mixing acoustic echo cancellation systems and methods
EP3804356A1 (fr) 2018-06-01 2021-04-14 Shure Acquisition Holdings, Inc. Réseau de microphones à formation de motifs
US11297423B2 (en) 2018-06-15 2022-04-05 Shure Acquisition Holdings, Inc. Endfire linear array microphone
WO2020061353A1 (fr) 2018-09-20 2020-03-26 Shure Acquisition Holdings, Inc. Forme de lobe réglable pour microphones en réseau
CN113841421A (zh) 2019-03-21 2021-12-24 舒尔获得控股公司 具有抑制功能的波束形成麦克风瓣的自动对焦、区域内自动对焦、及自动配置
US11558693B2 (en) 2019-03-21 2023-01-17 Shure Acquisition Holdings, Inc. Auto focus, auto focus within regions, and auto placement of beamformed microphone lobes with inhibition and voice activity detection functionality
EP3942842A1 (fr) 2019-03-21 2022-01-26 Shure Acquisition Holdings, Inc. Boîtiers et caractéristiques de conception associées pour microphones matriciels de plafond
EP3973716A1 (fr) 2019-05-23 2022-03-30 Shure Acquisition Holdings, Inc. Réseau de haut-parleurs orientables, système et procédé associé
JP2022535229A (ja) 2019-05-31 2022-08-05 シュアー アクイジッション ホールディングス インコーポレイテッド 音声およびノイズアクティビティ検出と統合された低レイテンシオートミキサー
JP2020202448A (ja) * 2019-06-07 2020-12-17 ヤマハ株式会社 音響装置および音響処理方法
EP4018680A1 (fr) 2019-08-23 2022-06-29 Shure Acquisition Holdings, Inc. Réseau de microphones bidimensionnels à directivité améliorée
US11506771B2 (en) * 2019-09-24 2022-11-22 GE Precision Healthcare LLC System and methods for flash suppression in ultrasound imaging
US11552611B2 (en) 2020-02-07 2023-01-10 Shure Acquisition Holdings, Inc. System and method for automatic adjustment of reference gain
US11706562B2 (en) 2020-05-29 2023-07-18 Shure Acquisition Holdings, Inc. Transducer steering and configuration systems and methods using a local positioning system
US11785380B2 (en) 2021-01-28 2023-10-10 Shure Acquisition Holdings, Inc. Hybrid audio beamforming system

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245459A (en) 1990-06-20 1992-01-02 Motorola Inc Echo canceller with adaptive voice switch attenuation
JPH04150127A (ja) 1990-10-09 1992-05-22 Oki Electric Ind Co Ltd 電話機の通話回路
JPH0638253A (ja) 1992-05-21 1994-02-10 Toshiba Corp エコーキャンセラ
JP3407455B2 (ja) 1995-02-15 2003-05-19 松下電器産業株式会社 エコーキャンセラ
US5668794A (en) * 1995-09-29 1997-09-16 Crystal Semiconductor Variable gain echo suppressor
JP3452341B2 (ja) 1995-12-05 2003-09-29 株式会社リコー エコーキャンセラ
SE505692C2 (sv) * 1995-12-18 1997-09-29 Ericsson Telefon Ab L M Förfarande och anordning för ekosläckning genom skattning av effekt hos residualsignal
JPH09275367A (ja) 1996-04-08 1997-10-21 Nec Corp エコーキャンセラ装置
JPH10285083A (ja) 1997-04-04 1998-10-23 Toshiba Corp 音声通信装置
SE511073C2 (sv) 1997-09-10 1999-08-02 Ericsson Telefon Ab L M Sätt och anordning för ekoestimering och undertryckning i telefonsystem
GB2330745B (en) * 1997-10-24 2002-08-21 Mitel Corp Nonlinear processor for acoustic echo canceller
US6961423B2 (en) * 2002-06-24 2005-11-01 Freescale Semiconductor, Inc. Method and apparatus for performing adaptive filtering

Also Published As

Publication number Publication date
US7203308B2 (en) 2007-04-10
JP4282260B2 (ja) 2009-06-17
US20040170271A1 (en) 2004-09-02
JP2003158476A (ja) 2003-05-30
EP1446894A1 (fr) 2004-08-18
EP1446894A4 (fr) 2006-02-01
DE60236367D1 (de) 2010-06-24
WO2003044978A1 (fr) 2003-05-30

Similar Documents

Publication Publication Date Title
EP1446894B1 (fr) Annuleur d'echo assurant une reduction plus poussee dans l'echo residuel
KR100524341B1 (ko) 음향 에코 제거기
US7856097B2 (en) Echo canceling apparatus, telephone set using the same, and echo canceling method
US5631900A (en) Double-Talk detector for echo canceller
JP2538176B2 (ja) エコ―制御装置
EP1298815B1 (fr) Processeur d'écho avec un générateur de pseudo-bruit de fond
US20030123674A1 (en) Gain control method for acoustic echo cancellation and suppression
US5764753A (en) Half-duplex controller
EP1955532A2 (fr) Procede et appareil de detection de diaphonie dans des systemes de communication mains-libres
JP4457639B2 (ja) エコーキャンセラ
US20040131178A1 (en) Telephone apparatus and a communication method using such apparatus
JPH10341190A (ja) エコー消去システム及び方法、並びに移動通信装置
JP4410819B2 (ja) エコーキャンセラ
JP2003324370A (ja) エコーキャンセラ
JP4403776B2 (ja) エコーキャンセラ
JP4475155B2 (ja) エコーキャンセラ
JP2003051879A (ja) 通話装置
EP0929174B1 (fr) Système commutateur amélioré à commande vocale
US7734035B2 (en) Method and apparatus for soft-response echo suppression
JP3404236B2 (ja) 拡声通話装置
JP5297396B2 (ja) 拡声通話装置
KR101009867B1 (ko) 통신 단말을 위한 음향반향 제거기 및 방법
KR20050041588A (ko) 가변적인 전송 패킷을 이용한 에코 제거 장치 및 방법
JP2011151629A (ja) 拡声通話装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20040116

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR

A4 Supplementary search report drawn up and despatched

Effective date: 20051216

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR

REF Corresponds to:

Ref document number: 60236367

Country of ref document: DE

Date of ref document: 20100624

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20110215

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 60236367

Country of ref document: DE

Effective date: 20110214

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20131121

Year of fee payment: 12

Ref country code: FR

Payment date: 20131120

Year of fee payment: 12

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60236367

Country of ref document: DE

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20150731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20150602

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20141201